The present invention relates to a storage system (also called a disk-array unit) for controlling storing of data into a storage unit and, in particular, to a technique for creating a replica of data in storage volume.
Conventionally, there has been a computer system comprising: a storage system (storage sub-system) for controlling the storing of the data in the storage unit; and a processor which serves as a host to conduct a read/write access to the data connected to the storage system through a communication means. In the said computer system, there is a replication function for creating replicas (replicated volumes) by a copying processing inside the storage system for the data of the storage volume installed in the storage area of the storage system.
In the storage system and the computer system equipped with the replication functions, there is the case where it is desired to create a plurality of replicas for the data on a storage volume. For example, the above-mentioned case is at the time when a plurality of replica volumes are created for the data of the storage volume which the processor uses for an on-line application and a plurality of created replica storage volumes are properly used for each processing such as a backup, a test, and a batch processing independently of the on-line application.
In the case where it is desired to create a plurality of replicas for the data of a storage volume using the conventional replication function, multiple instructions required for creating a plurality of replicas must be issued in time series to the storage system in accordance with instructions having been inputted by an operator (user) of the processor. That is, a procedure for: first issuing multiple pair-creation instructions to establish a plurality of pairs of a primary volume which serves as a copy source and a secondary-volume which serves as a copy destination; and establishing a plurality of pairs in the storage system is required.
For example, Japanese Patent Laid-Open No. 2000-132343 discloses a technique for creating the replicas by a copying processing inside the storage system, without interposing the processor for the data of the storage volume in the storage system. Also in this technique, the multiple instructions must be issued in the case where it is desirable that the plurality of replicas are created for the data of the storage volume.